71 Fast Back Recommissioning
- 937carrera
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Re: 71 Fast Back Recommissioning
Back on topic, did you have a chance to do any more work on this over the weekend ?
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
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- Posts: 109
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- Location: Cranleigh, Surrey UK
Re: 71 Fast Back Recommissioning
Been a few weeks due to my grandfather passing and i’ve been helping out alot down in Bognor with my nan and the rest of the family etc
Anyway, update time! I had an aircooled speciailst over today that i know, he’s found it’s only running on cylinders 1 and 3. He removed the ht leads individually with the engine running, when 1 or 2 were removed the engine note changed dramatically. When 3 and 4 were removed there was zero change.
I’m going to borrow a compression tester over the weekend hopefully and see if that shows anything. Oh the joys
On a more positive note he said i’d gapped the valves correctly and i’ve relocated the fuel filter down next to the gearbox as some of you recommended
Anyway, update time! I had an aircooled speciailst over today that i know, he’s found it’s only running on cylinders 1 and 3. He removed the ht leads individually with the engine running, when 1 or 2 were removed the engine note changed dramatically. When 3 and 4 were removed there was zero change.
I’m going to borrow a compression tester over the weekend hopefully and see if that shows anything. Oh the joys
On a more positive note he said i’d gapped the valves correctly and i’ve relocated the fuel filter down next to the gearbox as some of you recommended
Last edited by JackReddick on 11th May 2019 - 11:22am, edited 1 time in total.
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Re: 71 Fast Back Recommissioning
So this morning i’ve done a compression check across all four cylinders and got the below
Cyl 1 130 psi
Cyl 2 85 psi
Cyl 3 130 psi
Cyl 4 135 psi
Cylinder 2 has low compression. I also did a continuity test on the leads to 3 and 4 and ot appeared they were damaged/broken so swapped them for new leads but still no life in cylinders 3 and 4.
Any suggestions?
Cyl 1 130 psi
Cyl 2 85 psi
Cyl 3 130 psi
Cyl 4 135 psi
Cylinder 2 has low compression. I also did a continuity test on the leads to 3 and 4 and ot appeared they were damaged/broken so swapped them for new leads but still no life in cylinders 3 and 4.
Any suggestions?
- 937carrera
- Posts: 1190
- Joined: 7th June 2013 - 11:54pm
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Re: 71 Fast Back Recommissioning
Do you mean 3 and 4, or 2 and 4.....different to what you said before and quite importantJackReddick wrote: ↑11th May 2019 - 11:03am
Cylinder 2 has low compression. I also did a continuity test on the leads to 3 and 4 and ot appeared they were damaged/broken so swapped them for new leads but still no life in cylinders 3 and 4.
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
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- Posts: 109
- Joined: 12th April 2019 - 10:21pm
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Re: 71 Fast Back Recommissioning
Sorry it’s 3 and 4, i’ll amend my original post. Both the chlinders on the left hand side of the engine bay937carrera wrote: ↑11th May 2019 - 11:13amDo you mean 3 and 4, or 2 and 4.....different to what you said before and quite importantJackReddick wrote: ↑11th May 2019 - 11:03am
Cylinder 2 has low compression. I also did a continuity test on the leads to 3 and 4 and ot appeared they were damaged/broken so swapped them for new leads but still no life in cylinders 3 and 4.
Re: 71 Fast Back Recommissioning
First of all, condolences. Never easy to loose a relative. But its nice to hear your are returning focus to the car.
The below post would point us towards the two faulty cylinders.
Left hand furthest is number 3, nearest is number 4. I suspecting you've got the HT leads in the wrong order. Ive done it before and it resulted in an engine which ran like the one in your video.
The firing order is 1432.
The below post would point us towards the two faulty cylinders.
Just to clarify the cylinder numbers, stood at the back of the car. Right hand side the cylinder furthest from you is number 1. Nearest is number 2.broady_6 wrote: ↑22nd April 2019 - 1:38pmHave you checked the exhaust at each head port. Ideal from cold start him up and then touch each branch, before they get too hot. Obviously be very careful. If one is cold/colder than the rest then it'll pin point the problem. But as David said, a carb off again won't hurt. I've just done a two year resto on mine. Including ultra sonic carb cleaning. It drive pretty well, but hesitates, I've just pin pointed that the right hand carb is under fueling. So either a float issue, or something's found its way in.
Left hand furthest is number 3, nearest is number 4. I suspecting you've got the HT leads in the wrong order. Ive done it before and it resulted in an engine which ran like the one in your video.
The firing order is 1432.
The sultan of swing
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Re: 71 Fast Back Recommissioning
Thanks mate, i appreciate that.broady_6 wrote: ↑11th May 2019 - 11:24amFirst of all, condolences. Never easy to loose a relative. But its nice to hear your are returning focus to the car.
The below post would point us towards the two faulty cylinders.
Just to clarify the cylinder numbers, stood at the back of the car. Right hand side the cylinder furthest from you is number 1. Nearest is number 2.broady_6 wrote: ↑22nd April 2019 - 1:38pmHave you checked the exhaust at each head port. Ideal from cold start him up and then touch each branch, before they get too hot. Obviously be very careful. If one is cold/colder than the rest then it'll pin point the problem. But as David said, a carb off again won't hurt. I've just done a two year resto on mine. Including ultra sonic carb cleaning. It drive pretty well, but hesitates, I've just pin pointed that the right hand carb is under fueling. So either a float issue, or something's found its way in.
Left hand furthest is number 3, nearest is number 4. I suspecting you've got the HT leads in the wrong order. Ive done it before and it resulted in an engine which ran like the one in your video.
The firing order is 1432.
Yes that’s correct, cylinders 1 and 2 fire, with 2 having the lower compression.
I’ve had my hand on the exhaust port at the head by cylinder 4 and that was cold. I am yet to do it for culinder 3 but it’s currently chucking it down outside so i’ve run indoors to hide
Re: 71 Fast Back Recommissioning
If you follow the HT lead which has the red arrow pointing at it. It goes to the left hand head. Does it go to the cylinder furthest away from you or nearest the back of the car?
The sultan of swing
- 937carrera
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Re: 71 Fast Back Recommissioning
Beat me to it
If it isn't that then it's a carb problem, now we know it's one bank.
Here's a naff graphic for the cylinders
............||||||||||||-----------------
3...........................................1
4...........................................2
If it isn't that then it's a carb problem, now we know it's one bank.
Here's a naff graphic for the cylinders
............||||||||||||-----------------
3...........................................1
4...........................................2
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
- 937carrera
- Posts: 1190
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- Location: North Yorkshire
Re: 71 Fast Back Recommissioning
The rotor arm goes clockwise, this has better graphics
https://www.vanagon.org/distributor-firing-order
https://www.vanagon.org/distributor-firing-order
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
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- Posts: 109
- Joined: 12th April 2019 - 10:21pm
- Location: Cranleigh, Surrey UK
Re: 71 Fast Back Recommissioning
That lead goes to 3 (furthest from me)
If you pull the throttle with your head looking down the left carb you can see it squirt fuel in?
If you pull the throttle with your head looking down the left carb you can see it squirt fuel in?
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Re: 71 Fast Back Recommissioning
The guy who was looking yesterday swears blind there should be a solenoid on the side of each carb which mine don’t have. Is this correct? Or is he maybe thinking of another year/model?
Re: 71 Fast Back Recommissioning
Leads are correct then. Ill stand down!
Did you photograph the plugs when you had them out?
Next test take number 3 lead off the plug. Put a spark plug in the end of the lead, put the body of the plug on the block to earth it, have someone crank the engine of and check the spark.
Are they new plugs?
Yes you should see a squirt of fuel down each carb is you operate the throttle.
Did you photograph the plugs when you had them out?
Next test take number 3 lead off the plug. Put a spark plug in the end of the lead, put the body of the plug on the block to earth it, have someone crank the engine of and check the spark.
Are they new plugs?
Yes you should see a squirt of fuel down each carb is you operate the throttle.
The sultan of swing
Re: 71 Fast Back Recommissioning
We have a winner! The solenoid your missing is the idle cut off. Its a little plunger which blocks the jet to stop fuel getting into the engine when you turn the ignition off. It prevents the engine from running onJackReddick wrote: ↑11th May 2019 - 11:42amThe guy who was looking yesterday swears blind there should be a solenoid on the side of each carb which mine don’t have. Is this correct? Or is he maybe thinking of another year/model?
The sultan of swing
- 937carrera
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Re: 71 Fast Back Recommissioning
I would have expected there to be a cut off solenoid too (it stops fuel flow when the ignition is off)
Broady may just know the answer on that plug lead - if you swap 3 and 4 and it doesn't run, then can you get the engine to TDC for number 1 and let's see where the rotor arm is pointing
Broady may just know the answer on that plug lead - if you swap 3 and 4 and it doesn't run, then can you get the engine to TDC for number 1 and let's see where the rotor arm is pointing
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
Re: 71 Fast Back Recommissioning
The left hand carb has got a massive air leak if you've got nothing in that hole.
The sultan of swing
- 937carrera
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Re: 71 Fast Back Recommissioning
Lots of pictures of PDSIT32-34 carbs here, including the solenoid / cut off valves for you to compare to (I think that's what you have fitted)
https://www.ratwell.com/technical/DualCarbs.html
https://www.ratwell.com/technical/DualCarbs.html
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
Re: 71 Fast Back Recommissioning
Just to the left of the accelerator pump square that hole is where the cut of solenoid goes
The sultan of swing
Re: 71 Fast Back Recommissioning
Theyre the type 4 version and has quite a few bits not featured on the type 3 version937carrera wrote: ↑11th May 2019 - 11:55amLots of pictures of PDSIT32-34 carbs here, including the solenoid / cut off valves for you to compare to (I think that's what you have fitted)
https://www.ratwell.com/technical/DualCarbs.html
The sultan of swing
- 937carrera
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Re: 71 Fast Back Recommissioning
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
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- Posts: 109
- Joined: 12th April 2019 - 10:21pm
- Location: Cranleigh, Surrey UK
Re: 71 Fast Back Recommissioning
This is my left carb
- 937carrera
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Re: 71 Fast Back Recommissioning
See, I did say I know nothing937carrera wrote: ↑13th April 2019 - 9:40pmI'm a type 4 owner so less knowledgeable on the type 3's
The link I posted is referring to type 3 solenoids, with a source for NOS
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
- 937carrera
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Re: 71 Fast Back Recommissioning
What's that new shiny brass bit and the unconnected spade in picture 1 ?
David
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
1974 412LS Variant
1973 412LE 4 door Fastback / Saloon
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- Posts: 109
- Joined: 12th April 2019 - 10:21pm
- Location: Cranleigh, Surrey UK
Re: 71 Fast Back Recommissioning
The disconnected spade is for the choke. The shiny brass bit i assume has been fitted by the previous owner to block off where the solenoid should be? The right hand carb is exactly the same937carrera wrote: ↑11th May 2019 - 12:08pmWhat's that new shiny brass bit and the unconnected spade in picture 1 ?
If the solenoids you mentioned in that other post for the t25 fit from vwheritage, i’ll pop down there monday as they aren’t far from me
Re: 71 Fast Back Recommissioning
When you rebuilt the carbs, did you take that brass bit out?
Wiring wise, extend the wire from the choke around to the cut off solenoid when you fit them.
Yeah these will fit https://www.vwheritage.com/058129413e-i ... c-vw-spare
Wiring wise, extend the wire from the choke around to the cut off solenoid when you fit them.
Yeah these will fit https://www.vwheritage.com/058129413e-i ... c-vw-spare
The sultan of swing